1. Field of the Invention
The invention concerns a method of real-time broadcasting of multimedia files during a video conference, without breaking communication, and a man-machine interface for implementing the said method.
2. Description of the Related Art
To conduct a video conference, use is made of a video conference terminal conventionally consisting of computer equipment, dedicated or not. It may therefore be a case of a computer of the PC type equipped with video conference functions. The computer is then coupled to audio and video signal capture sources (camera, microphones). The computer is also equipped with software for processing the signals captured and processing the signals received, means of connection to a telecommunication network and a man/machine interface for displaying on the screen a so-called “local” window and at least one so-called “distant” window.
In the remainder of the description a video conference terminal will be spoken of in order to designate any terminal equipped with means for establishing video conference communications through a telecommunication network with one or more other video conference terminals.
During a video conference, a participant, having a video conference terminal, may wish to broadcast in real time a data file, in particular a multimedia file, to his fellow participants. Broadcasting is spoken of to designate the fact that the receiver never has the broadcast file available to it.
The sending participant is hereinafter designated as the “sender”. The multimedia files are for example video files which the participant has recorded and which he wishes to comment on, musical extracts, or any other multimedia file that the terminal can use. These files are, for example, videos to the MPEG-1 format or music to the MP3 format.
One solution currently adopted in video conference terminals consists of transmitting the multimedia file in its entirety to the participant through a data channel separate from the audio and video channels of the communication. The participants then receive the file as it exists on the computer of the sender.
This solution raises several problems:
A first problem stems from the fact that the operation does not truly take place in real time with the current communication, the transmission time depends on the size of the file and the bandwidth available on the separate channel used.
In addition, the sender is obliged to perform several operations and manipulations which are not very economic, the consequence of which is to momentarily break the communication.
Moreover, there is a risk of the receivers not having available equipment capable of using these files (for example: the sender wishes to send a video coded with the MPEG-1 standard to the receiver, the receiver does not have an MPEG-1 decoder and therefore he cannot decode the file).
And finally, the sender makes his multimedia file available to his receivers, which he would wish to be able to prevent.
To summarise, this solution amongst other things poses problems of real time, economics, breakage of communication and security of operation.
Another solution is afforded by standards of the T.120 type. According to these standards, it is possible to effect a sharing of applications between video conference participants.
The sender has for this purpose a list of primitives enabling him to transmit the events which he generates, 2D images or screen captures of the video conference terminal which he is using. However, the sender does not have the possibility of controlling the bandwidth which he uses and does not have the possibility of transmitting audio data.
In addition, if the receiver is not able to support the document sharing standards, the broadcasting of a multimedia file is impossible.